How to unhide files hidden by viruses

I have Often got some problems in my computer, including the virus that infected the files. The effects of virus can be so various, one of them is hiding our file. so it become inaccessible. There are some tricks to retrieve that files and folders as below :

1. Open command line using Start->Run and type cmd
2. Go to drive of hidden files for example in drive D:
3. type dir /a to view all files including the hidden files
4. type attrib -r -h -s *.* /s /d to unhide all hidden files